Small Change for Stuart by Lissa Evans
As if being tiny and also having S.Horten as your name isn't bad enough, ten-year-old Stuart Horten is moved (by his very clever, but not very sensible parents) to Beeton, far away from all his friends. But in Beeton starts the strangest adventure of Stuart's life as he is swept up in a quest to find his uncle's old workshop - his famous magician, and also very short, uncle, that is...